The phone is not a tool. It's a slot machine you keep in your pocket. The only way to win is to make it boring.

Gray is a feature

Turn off color. Kill the badges. Move every app off the first screen. A boring phone stops reaching for you, which is the entire battle.

Then do the work

Attention follows structure. Put the timer on, block the pings, and let the only interesting thing in the room be the thing you're actually doing.